Heat exchanger for refrigerator and refrigerator having the same

ABSTRACT

The present disclosure relates to a heat exchanger for refrigerator and a refrigerator having the same. The heat exchanger for refrigerator includes a plurality of heat transfer continuously arranged in multiple stages from a windward side to a leeward side, wherein the heat transfer fins disposed in the lower stage are offset in one of the column direction and the width direction from the plane&#39;s perspective.

CROSS-REFERENCE TO RELATED APPLICATIONS AND CLAIM OF PRIORITY

This application is a 371 of International Application No. PCT/KR2017/000465 filed Jan. 13, 2017, which claims priority to Japanese Patent Application No. 2016-004438 filed Jan. 13, 2016; Japanese Patent Application No. 2016-134622 filed Jul. 6, 2016; Japanese Patent Application No. 2016-150212 filed Jul. 29, 2016 and Japanese Patent Application No. 2016-245566 filed Dec. 19, 2016, the disclosures of which are herein incorporated by reference in their entirety.

BACKGROUND 1. Field

The present disclosure relates to a heat exchanger for a refrigerator and a refrigerator having the same.

2. Description of Related Art

The present disclosure relates to a heat exchanger for a refrigerator and a refrigerator having the same. The heat exchanger for a refrigerator, as disclosed in Japanese Patent Publication No. 2014-159884, includes a heat transfer pipe through which a refrigerant flows, and a plurality of heat transfer fins continuously arranged along the heat transfer pipe.

Among these heat exchangers, there are heat exchangers in which heat transfer fins are arranged in multiple stages from a windward side in the upstream of an air flow direction to a leeward side in the downstream of the air flow direction.

In such heat exchangers, the heat transfer fins have face-to-face body portions and inclined portions formed by bending windward side end portions and leeward side end portions of the body portions in parallel.

This configuration improves the efficiency of heat exchange between the heat transfer fins and air because airflow is lost when the air is introduced from the inclined portion of the windward side to the body portion or from the body portion to the inclined portion of the leeward side.

In the heat exchangers configured as described above, when the heat transfer fins positioned at the neighboring upper and lower stages are closely examined, air flows along a leeward side inclined portion of the heat transfer fin at the lower stage, and then flows along a windward side inclined portion of the heat transfer fin at the upper stage, and then the flow direction of air is changed by the body portion of the heat transfer fin at the upper stage.

However, as described above, since the windward side inclined portion and the leeward side inclined portion are parallel to each other, before the air reaches the body portion, the air flows in the same direction along the leeward side inclined portion of the heat transfer fin at the lower stage and the windward side inclined portion of the heat transfer fin at the upper stage, developing a thermal boundary layer therebetween.

Therefore, even if the flow direction of the air is changed by the body portion, the already developed thermal boundary layer cannot be effectively broken down, and thus, the heat exchange efficiency cannot be greatly improved in practice.

SUMMARY

The present disclosure provides a heat exchanger for a refrigerator and a refrigerator having the same, capable of improving heat exchange efficiency more than the prior art.

In accordance with an aspect of the present disclosure, a heat exchanger for a refrigerator and refrigerator having the same is provided. The heat exchanger for refrigerator includes a plurality of heat transfer fins continuously arranged in multiple stages from a windward side to a leeward side, wherein the heat transfer fins disposed at upper and lower stages adjacent to each other are offset in one of a column direction and a width direction from the plane's perspective.

The heat transfer fins disposed at the upper and lower stages adjacent to each other may be offset by a first distance in the column direction and offset by a second distance in the width direction.

The heat transfer fins positioned on the windward side may be spaced apart from each other at a first fin pitch, wherein the plurality of heat transfer fins positioned in multiple stages on the leeward side are spaced apart from each other at a second fin pitch smaller than the first fin pitch.

The heat transfer fins disposed at the upper and lower stages adjacent to each other among the heat transfer fins spaced apart from each other by the second fin pitch may be offset by a predetermined distance in one of the column direction and the width direction.

The predetermined distance in the width direction may be equal to or less than ½ of a height of the heat transfer fin.

Leeward side end portions of the heat transfer fins may be folded obliquely with respect to an air flow direction.

The heat transfer fins may include body portions positioned on the windward side and folded portions formed by being folded from the leeward side end portions of the body portions, wherein the folded portion is folded at an angle of no less than 5 degrees and no more than 20 degrees with respect to the body portion.

In the heat transfer fins disposed at the upper and lower stages adjacent to each other among the heat transfer fins disposed at the second fin pitch, windward side end portions of the heat transfer fins of the upper stage and leeward side end portions of the heat transfer fins of the lower stage may be spaced apart from each other by less than 1 mm in a vertical direction.

The heat transfer fin may include a cut-and-erected portion that is cut and erected toward a heat transfer fin facing the heat transfer fin in the column direction.

Height from a proximal end to a distal end of the cut-and-erected portion may be smaller than the fin pitch between the heat transfer fins continuously disposed and facing each other.

At least one of an upper end portion and a lower end portion of the cut-and-erected portion may form a concave-convex shape.

The heat exchanger for refrigerator may further include a pair of heat transfer pipes passing through the heat transfer fins, wherein a first center line in the width direction of the heat transfer fins and a second center line between the pair of heat transfer pipes are spaced apart from each other by a predetermined distance.

The heat transfer fins form a first heat transfer fin in which the first center line may be positioned on one side in the width direction of the second center line and a second heat transfer fin in which the first center line is positioned on the other side in the width direction of the second center line.

Among the heat transfer fins disposed at upper and lower stages adjacent to each other, the heat transfer fin positioned at the upper stage may be formed as one of the first heat transfer fin and the second heat transfer fin and the heat transfer fin positioned at the lower stage is formed as the other of the first heat transfer fin and the second heat transfer fin.

Among the heat transfer fins disposed at the upper and lower stages adjacent to each other, the first centerline of the heat transfer fins positioned at one of the upper stage and the lower stage may be aligned with the second centerline, and wherein the heat transfer fins positioned at the other one of the upper stage and the lower stage are formed as one of the first heat transfer fin and the second heat transfer fin.

A heat exchanger for refrigerator and refrigerator having the same according to the present disclosure may have more improved heat exchange efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view illustrating a heat exchanger for refrigerator according to a first embodiment of the present disclosure;

FIG. 2 is a schematic view illustrating a portion of the heat exchanger for refrigerator according to the first embodiment of the present disclosure;

FIG. 3 is a view illustrating fin pitch and spaced distance of the heat transfer fins applied to the heat exchanger for refrigerator according to the first embodiment of the present disclosure;

FIG. 4 shows experimental data indicating correlations of presence or absence of offset and a bridge in the heat exchanger for refrigerator according to the first embodiment of the present disclosure;

FIG. 5 shows experimental data indicating correlations between a spaced distance and a bridge in the heat exchanger for refrigerator according to the first embodiment of the present disclosure;

FIG. 6 is a schematic view illustrating the heat transfer fin applied to the heat exchanger for refrigerator according to the first embodiment of the present disclosure;

FIG. 7 shows experimental data indicating correlations of presence or absence of surface treatment of the heat transfer fin and a bridge in the heat exchanger for refrigerator according to the first embodiment of the present disclosure;

FIG. 8 is a schematic view illustrating a modification of the heat transfer fin of the heat exchanger for refrigerator according to the first embodiment of the present disclosure;

FIG. 9 is a schematic view illustrating another modification of the heat transfer fin of the heat exchanger for refrigerator according to the first embodiment of the present disclosure;

FIG. 10 is a schematic view illustrating a heat transfer fin applied to a heat exchanger for refrigerator according to a second embodiment of the present disclosure;

FIG. 11 shows experimental indicating an effect of the heat transfer fin applied to the heat exchanger for refrigerator according to the second embodiment of the present disclosure;

FIG. 12 is a schematic view illustrating a modification of the heat transfer fin of the heat exchanger for refrigerator according to the second embodiment of the present disclosure;

FIG. 13 is a schematic view illustrating a heat transfer fin applied to a heat exchanger for refrigerator according to a third embodiment of the present disclosure;

FIG. 14 is a schematic view illustrating a folded portion in the heat transfer fin applied to the heat exchanger for refrigerator according to the third embodiment of the present disclosure;

FIG. 15A and 15B are schematic views of a modification of the heat transfer fin of the heat exchanger for refrigerator according to the third embodiment of the present disclosure;

FIGS. 16A and 16B are schematic views of another modification of the heat transfer fin of the heat exchanger for refrigerator according to the third embodiment of the present disclosure;

FIG. 17 is a schematic view illustrating a part of a heat exchanger for refrigerator according to a fourth embodiment of the present disclosure;

FIG. 18 is a schematic view illustrating a heat transfer fin applied to the heat exchanger for refrigerator according to the fourth embodiment of the present disclosure;

FIG. 19 is a schematic view illustrating a modification of the heat transfer fin of the heat exchanger for refrigerator according to the fourth embodiment of the present disclosure;

FIGS. 20A and 20B are schematic views illustrating another modification of the heat transfer of the heat exchanger for refrigerator according to the fourth embodiment of the present disclosure; and

FIG. 21 is a schematic view illustrating another modification of the heat transfer fin of the heat exchanger for the refrigerator according to the fourth embodiment of the present disclosure.

DETAILED DESCRIPTION

Hereinafter, various embodiments of a heat exchanger for refrigerator according to the present disclosure will be described in detail with reference to accompanying drawings.

First Embodiment

A heat exchanger 100 according to the first embodiment of the present disclosure is used in a refrigerator including a storage room such as a refrigerating room or a freezing room, and constitutes a refrigeration cycle together with a compressor and a condenser to be used as an evaporator for cooling air to be supplied to the storage room.

Hereinafter, the heat exchanger 100 for refrigerator will be referred to as an evaporator 100 for convenience of explanation.

In the embodiment of the present disclosure, a fan for circulating air is disposed above the evaporator 100 to transfer air in the storage room to the evaporator 100 and transfer the air cooled by the evaporator 100 back to the storage room. The position of the fan may vary according to the design.

Referring to FIG. 1, the evaporator 100 is formed as a fin & tube type heat exchanger including a heat transfer pipe 10 and a plurality of heat transfer fins 20 installed in the heat transfer pipe 10.

The heat transfer pipe 10 allows a refrigerant to pass through and exchange heat with the air. In this embodiment, the heat transfer pipe 10 is formed as an S-shaped pipe, which is formed by being folded into an S shape. In this embodiment, since the air flows upward and passes through the evaporator 100, the lower side of the evaporator 100 is a windward side that is an upstream side of an air flow direction and an upper side of the evaporator 100 is a leeward side that is the downstream side of the air flow direction. Since the heat transfer pipe 10 extends in the S-shape from the leeward side to the windward side and extends again in the S-shape from the windward side to the leeward side, the cold refrigerant flows from the leeward side to the windward side along the heat transfer pipe 10, and then flows backward from the windward side to the leeward side in the S shape.

The refrigerant that has exchanged heat with the air is separated into a liquid refrigerant and a gaseous refrigerant by an accumulator A disposed between the evaporator 100 and the compressor, and the gaseous refrigerant is suctioned into the compressor.

The heat transfer fins 20 are disposed at the heat transfer pipes 10 to increase an area for heat exchange between the evaporator 100 and the air. The heat transfer fins 20 are formed in a thin plate shape having heat conductivity, and the heat transfer pipe 10 is installed through the heat transfer fins 20.

Here, the plurality of heat transfer fins 20 consecutively arranged in parallelalong linear portions of the heat transfer pipe 10, and the heat transfer fins 20 consecutively arranged in this manner are formed in multiple stages from the windward side to the leeward side.

More specifically, the plurality of heat transfer fins 20 are arranged such that the fin pitch on the leeward side is narrower than on the windward side. In this embodiment, the heat transfer fins 20 of a lower stage section SL (9th stage to 12th stage in this embodiment) on the windward side are spaced at a first fin pitch PL, the heat transfer fins 20 of an upper stage section SH (1st stage to 4th stage in this embodiment) on the windward side are spaced at a second fin pitch PH, and the heat transfer fins 20 of a middle stage section SM (5th stage to 8th stage in this embodiment) between the lower stage section SL on the windward side and the upper stage section SH on the windward side are spaced at a third fin pitch PM.

The term pin pitch refers to a distance from a side surface of one heat transfer fin 20 to a side surface of another neighboring heat transfer fin 20.

More specifically, for example, the first fin pitch PL may be about 10 mm to about 15 mm, the second fin pitch PH may be about 5 mm to about 7.5 mm smaller than the first fin pitch PL, and the third fin pitch PM may be about 7.5 mm to about 10 mm in the middle of the first fin pitch PL and the second fin pitch PH.

Referring to FIG. 3, in the evaporator 100 of this embodiment having a plurality of stages in which the heat transfer fins 20 are spaced at the second fin pitch PH, the heat transfer fins 20 arranged in the upper and lower stages adjacent to each other are offset by a predetermined distance in the column direction.

In other words, when the heat transfer fins 20 of the upper stage section SH are viewed from a vertical direction, the heat transfer fins 20 adjacent to each other in the vertical direction are arranged so as not to overlap each other.

In this embodiment, an offset distance X is set to be half of the second fin pitch PH. Specifically, when the heat transfer fins 20 provided in a stage of the upper stage section SH are viewed from the vertical direction, they are each located in the middle of two heat transfer fins 20 arranged on the upper stage to be adjacent to each other in the column direction. In other words, in the upper stage section SH, when each heat transfer fin 20 in k stage is viewed from the vertical direction, the heat transfer fin 20 of the k stage is positioned in the middle of two heat transfer fins 20 of k−1 stage adjacent to each other in column direction.

In addition, the heat transfer fins 20 disposed in the lower stage section SL are not offset in the column direction so as to prevent clogging between the vertically adjacent heat transfer fins 20 due to the frost.

In this embodiment, the heat transfer fins 20 disposed in the middle stage section SM are offset in the column direction in the same manner as the heat transfer fins 20 of the upper stage section SH as described above. However, this is an example, and the heat transfer fins 20 may not be offset in the column direction, or the offset distance may be appropriately changed to be different from the current drawing.

FIG. 4 shows experimental data of comparison between a case of offsetting the heat transfer fins 20 arranged in the upper stage area SH and a case of not offsetting the heat transfer fins 20.

The experimental data shows that a bridge (hereinafter referred to as a same column fin-to-fin bridge) that may occur between the heat transfer fins 20 adjacent to each other in the column direction is suppressed by offsetting the heat transfer fins 20. This is because water droplets formed on the heat transfer fins 20 adjacent to each other in the column direction are dragged by the surface tension down to the upper end of the heat transfer fins 20 positioned at the lower side stage.

On the other hand, as described above, by offsetting the heat transfer fins 20, a bridge may be generated between the heat transfer fins 20 disposed at the upper and lower stages adjacent to each other (hereinafter, referred to as upper and lower stages fin-to-fin bridge).

FIG. 5 shows experimental data indicating correlations between a spaced distance Z of the heat transfer fins 20 arranged at the upper and lower stages adjacent to each other in the vertical direction and the upper and lower stages fin-to-fin bridge, where the heat transfer fins 20 are arranged in multiple stages at the second fin pitch PH, i.e., the heat transfer fins 20 are located in the upper stage area SH.

The spaced distance Z is a distance from the lower end of a heat transfer fin 20 to the upper end of a heat transfer fin 20 positioned under the former heat transfer fin 20.

As can be seen from the above experimental data, the upper and lower stages fin-to-fin bridges may be suppressed when the distance Z is less than about 1 mm in a state where the heat transfer fins 20 are offset. Of course, as shown in FIG. 5, the upper and lower stages fin-to-fin bridges may be suppressed when the spaced distance Z is increased (for example, about 3 mm or more). However, in this case, the same column fin-to-fin bridge is generated as shown in FIG. 4.

In the plurality of stages in which the heat transfer fins 20 are disposed at the second fin pitch PH as derived from the above experimental results, by offsetting the heat transfer fins 20 arranged at the upper and lower ends adjacent to each other by half the second fin pitch PL in the column direction and at the same time, staying the spaced distance Z less than about 1 mm, both the upper and lower stages fin-to-fin bridge and the same column fin-to-fin bridge may be suppressed at the same time.

Next, each heat transfer fin 20 will be described.

Each of the heat transfer fins 20, as shown in FIG. 6, includes a through hole 21 into which the heat transfer pipe 10 is inserted without moving. In this embodiment, each of the heat transfer fins 20 includes a pair of through holes 21, and two rows of the heat transfer pipes 10 installed at each stage pass through each heat transfer fin 20.

In this embodiment, each of the heat transfer fins 20 is formed in a rectangular shape. However, the shape of the heat transfer fin 20 may be variously changed to e.g., an ellipse or a square.

In this embodiment, on the heat transfer fins 20 arranged at the second fin pitch PH as described above, that is, the heat transfer fins 20 disposed in the upper stage section SH, surface treatment is performed to draw water drops attached to the heat transfer fins 20 positioned at the upper stage.

In addition, although the surface treatment is not essential for the heat transfer fins 20 disposed in the middle stage section SM and the lower stage section SL, in this embodiment, the surface treatment is performed on all the heat transfer fins 20 disposed in the upper stage section SH, the middle stage section SM and the lower stage section SL so that the heat transfer fins 20 may be easily managed.

More specifically, each of the heat transfer fins 20 is provided with a coarse portion 22 formed at least on an outer portion of the heat transfer fin 20 for attracting water droplets according to the surface tension. In this embodiment, as shown in FIG. 6, the coarse portion 22 is formed on the entire front and back surfaces of the heat transfer fin 20.

The coarse portion 22, for example, is preferably formed in vertical lines parallel to the gravity direction to have predetermined roughness or predetermined width through hair line processing, or the like. Examples of a specific surface treatment method include a method of rolling the front and back surfaces of the heat transfer fin 20, a method of file trimming, and a method of sandblasting.

FIG. 7 shows experimental data indicating correlations of the presence or absence of the coarse portion 22 and the bridge.

As a result of the above experiment, it may be seen that the upper and lower stages fin-to-fin bridges are suppressed by forming the coarse portion 22 at the heat transfer fin 20.

The evaporator 100 configured as described above reduces the pitch of the leeward side fins than the pitch of the windward side fins, so that a heat exchange efficiency is improved, and by offsetting the heat transfer fins 20 of the upper stage section SH to each other by half of the second fin pitch in the column direction and staying the spaced distance Z less than about 1 mm, both the upper and lower stages of the fin-to-fin bridge and the same column fin-to-fin bridge may be suppressed.

In addition, since the coarse portion 22 is formed on the front and back surfaces of the heat transfer fins 20, the upper and lower stages fin-to-fin bridges may be more reliably suppressed.

In addition, since the coarse portion 22 is formed on the entire surface of the heat transfer fin 20, when for example, the coarse portion 22 is formed through the rolling, it is advantageous in terms of economy as compared to a case of forming the coarse portion 22 in a portion of the heat transfer fin 20.

However, the present disclosure is not limited to the above embodiment.

In the above embodiment, the heat transfer fins are arranged in four stages in each of the upper stage section, the lower stage section and the middle stage section. However, the present disclosure is not limited thereto. It is possible to have one stage of the heat transfer fins arranged in the lower stage section, and to remove the middle stage section. Further, four or more stages of heat transfer fins may be arranged in each section.

In addition, in the above embodiment, the offset distance is half the fin pitch of the upper stage section, but the offset distance may be appropriately changed.

Also, in the above embodiment, the coarse portion is formed on the entire front and back surfaces of the heat transfer fin, but the coarse portion may be formed on only one of the front surface and the back surface.

Also, it is not necessary to form the coarse portion on the entire surface of the heat transfer fin as in this embodiment, and it is preferable to form a coarse portion on at least the outer side of the heat transfer fin through a mask or the like.

More specifically, as in the embodiment shown in FIG. 8, the coarse portion 22 may be formed on an upper end portion and a lower end portion of the heat transfer fin 20, and the coarse portion 22 may be formed as long as a predetermined distance inward from the upper end and the lower end of the heat transfer fin 20.

In addition, the coarse portion may be formed on side end portions of the heat transfer fin in addition to the upper end portion and the lower end portion, or the coarse portion may be formed only in the upper end portion of the heat transfer fin.

In addition, as shown in FIG. 8, the coarse portion 22 is formed from one end to the other end in the upper end portion and the lower end portion of the heat transfer fin 20. However, the present disclosure is not limited thereto. The coarse portion may be limitedly formed at a center portion of the upper end portion and the lower end portion of the heat transfer fin.

In this embodiment, the heat transfer fin 20 includes the coarse portion 22 formed by rolling or the like. However, as shown in FIG. 9, the heat transfer fin 20 may include a plurality of slits formed on the outer portion of the heat transfer fin 20 through machining or the like.

Here, the slits 23 may be spaced at regular intervals or spaced apart at irregular intervals.

In addition, it is also possible to perform surface treatment on the upper stage section or the middle stage section as in the above embodiment without offsetting the heat transfer fins disposed at the upper and lower stages adjacent to each other in the column direction.

With this configuration, although the effect is smaller than that of the above embodiment, there is a merit that an installation work of each heat transfer fin may be simplified while suppressing generation of the bridge.

In addition, the surface treatment as described in the above embodiment is not necessarily performed for the heat transfer fin. When the surface treatment is not performed, generation of the bridge may be suppressed and a rise in cost may be prevented.

Second Embodiment

Hereinafter, a second embodiment of a heat exchanger for refrigerator according to the present disclosure will be described.

The heat exchanger for refrigerator of the second embodiment has a heat transfer fin different from that of the first embodiment.

Hereinafter, the detailed structure of the heat transfer fin applied to the second embodiment of the heat exchanger for refrigerator according to the present disclosure will be described.

Referring to FIG. 10, the heat transfer fin 20 of this embodiment is formed in a flat plate shape, in which the windward side end portion of the heat transfer fin 20 is not folded and the leeward side end portion of the heat transfer fin 20 is folded obliquely with respect to a flow direction of air, making the flow direction of the air passing between the heat transfer fins 20 changed so that the air flows toward one side surface of the heat exchange fins positioned at the upper end thereof.

More specifically, each heat transfer fin 20 has a body portion 24 positioned on the windward side and a folded portion 25 folded at an angle from the leeward side end portion 241 of the body portion 24.

The body portion 24 is formed in a flat plate shape. In this embodiment, the body portions 24 of the heat transfer fins 20 adjacent to each other in the column direction are spaced from each other by a predetermined fin pitch P, and the body portions 24 of the heat transfer fins 20 positioned at the upper and lower stages adjacent to each other overlap in the vertical direction. Specifically, the heat transfer fins 20 arranged in the column direction are equally spaced with a predetermined fin pitch P, and the heat transfer fins 20 arranged at the upper and lower stages adjacent to each other are not offset in the column direction.

The folded portion 25 is folded from the leeward side end portion 241 of the body portion 24 through an R bending process. The folded portion 25 is folded so that an angle θ (hereinafter also referred to as a folding angle θ) formed by an extending direction of the folded portion 25 and an extending direction of the body portion 24 is about 5 degrees or more and about 20 degrees or less.

Here, the folded portion 25 of each heat transfer fin 20 is folded at the same folding angle θ, and a leading end 251 of the folded portion 25, that is, the upper end of the heat transfer fin 20 (a portion positioned at the most leeward side) is folded so that the upper end of the heat transfer fin 20 is positioned in the approximately middle of the heat transfer fins 20 adjacent to an upper end of the folded portion 25. Also, a spaced distance Z between the leading end 251 of the folded portion 25 and the lower end of the heat transfer fin 20 positioned at an upper side of the leading end 251 is set to less than about 1 mm as in the first embodiment.

FIG. 11 shows experimental data indicating correlations between the folding angle θ of the folded portion 25 and a pressure loss ΔP and correlations between the folding angle θ of the folded portion 25 and an amount of heat transfer Q.

As can be seen from the above experimental data, the pressure loss ΔP gradually increases as the folding angle θ of the folded portion 25 is increased from 0 degrees. On the other hand, it is seen that the amount of heat transfer Q increases as the folding angle θ increases from 0 degrees to 15 degrees such that the heat exchange efficiency is improved by about 3.5%, and it does not increase more than that.

Therefore, in the evaporator for refrigerator in which air velocity of air flowing into the evaporator is relatively small, it is preferable to set the folding angle θ to about 5 degrees or more and about 15 degrees or less in order to suppress the pressure loss ΔP as much as possible while increasing the amount of heat transfer Q.

The evaporator 100 having the above structure is configured such that the windward side end portion of the heat transfer fin 20 is not folded and the leeward side end portion of the heat transfer fin 20 is folded toward the heat transfer fin 20 positioned at the upper stage. Therefore, after the air flows along the folded portions 25 of the heat transfer fins 20 at a certain stage, the flow direction of the air is changed by the body portions 24 of the heat transfer fins 20 positioned at the upper stage in a state where the thermal boundary layer is not sufficiently developed.

Accordingly, the thermal boundary layer may be effectively broken through the upper stage heat transfer fin 20 s on the upper stage, and the heat exchange efficiency may be improved more than with the conventional technology.

In addition, since the air flowing along the folded portions 25 of the heat transfer fins 20 positioned in a stage is introduced obliquely into the body portions 24 of the heat transfer fins 20 positioned at the upper stage, the air may easily reach the leading edge of the heat transfer fin 20 in the upper stage, facilitating improvement of the heat exchange efficiency by a leading edge effect.

That is, according to the above-described structure, improvement in both the heat exchange efficiency by the turbulence and the heat exchange efficiency by the leading edge may be attained.

In addition, since the heat transfer fin 20 is folded only at the leeward side end portion, a manufacturing process of the heat transfer fin 20 is simplified.

Since the leading end 251 of the folded portion 25 is positioned approximately in the middle of the adjacent heat transfer fins 20 in the upper stage and the spaced distance Z between the leading ends 251 of the folded portions 25 and the lower ends of the heat transfer fins 20 positioned at the upper stage is set to be less than about 1 mm, both the upper and lower stages fin-to-fin bridge and the same column fin-to-fin bridge may be suppressed as in the first embodiment.

In the above embodiment, the heat transfer fins 20 disposed in the upper and lower stages adjacent to each other are not offset in the column direction. However, the present disclosure is not limited thereto. It is also possible that the heat transfer fins 20 may be offset in the column direction as shown in FIG. 12.

Here, the folding angle θ of the folded portion 25 is set to about 5 degrees or more and about 20 degrees or less, and the heat transfer fins 20 disposed in the upper and lower stages adjacent to each other are offset in the column direction. The offset distance X is set so that the leading end 251 of the folded portion 25 is positioned approximately in the middle of the adjacent heat transfer fins 20 in the upper stage.

In the above embodiment, the folding angle of each of the heat transfer fins is set to be the same. However, the folding angle of some heat transfer fins may be set differently from the folding angle of the remaining heat transfer fins.

In addition, the folded portion of the above embodiment is folded from to the body portion, but it is also possible for the folded portion to be curved from the body portion.

Third Embodiment

Next, a third embodiment of the heat exchanger for refrigerator according to the present disclosure will be described.

The heat exchanger for refrigerator according to the third embodiment of the present disclosure differs from the above embodiments in the configuration of heat transfer fins. Hereinafter, a detailed configuration of the heat transfer fin applied to the heat exchanger according to the third embodiment of the present disclosure will be described.

The heat transfer fin 20 of this embodiment is formed in a flat plate shape as shown in FIG. 13, and includes a cut-and-erected portion 26 formed by being cut and standing up toward the opposite heat transfer fin 20 in the column direction. Here, each heat transfer fin 20 includes a pair of cut-and-erected portions 26 formed on opposite sides of the heat transfer fin 20, and the cut-and-erected portions 26 are cut and erected from the heat transfer fin 20 in the same direction.

The cut-and-erected portions 26 are formed by grooving and erecting the left and right sides of the heat transfer fin 20, and height L of the cut-and-erected portion 26, that is, length L from a proximal end to a distal end of the cut-and-erected portion 26 is set to be smaller than the fin pitch between the heat transfer fins 20 so that the cut-and-erected portion 26 does not interfere with the adjacent heat transfer fin 20 in the column direction.

As disclosed in FIG. 14, each cut-and-erected portion 26 includes a face plate portion 261 formed in parallel with the air flow direction, that is, in parallel with the vertical direction, and the cut-and-erected portion 26 is erected perpendicularly to a face plate portion 201 of the heat transfer fin 20.

The face plate portion 261 of the cut-and-erected portion 26 does not necessarily have to be perpendicular to the face plate portion 201 of the heat transfer fin 20, and it is also possible for the face plate portion 261 of the cut-and-erected portion 26 to be formed to be inclined with respect to the face plate portion 201 of the heat transfer fin 20.

In the cut-and-erected portion 26 of the present embodiment, the upper end portion (the leeward side end portion) and the lower end portion (the windward side end portion) form a plurality of concave-convex shapes. More specifically, the upper end portion and the lower end portion of the cut-and-erected portion 26 form a saw-tooth shape in which a plurality of triangular concave-convex shapes are formed. In addition, the plurality of the concave-convex shapes may not be formed on the upper end portion of the cut-and-erected portion 26, but on the lower end portion of the cut-and-erected portion 26.

Since the heat transfer fin 20 includes the cut-and-erected portion 26, the evaporator 100 configured as described above may improve the effect of the leading edge, such that a heat exchange performance may be improved.

In addition, since the lower end portion of the cut-and-erected portion 26 has the saw-tooth shape, the leading edge effect may be further increased.

In addition, since the upper end portion of the cut-and-erected portion 26 is formed in the saw-tooth shape in the same manner as the lower end portion, an installation work of the heat transfer fin 20 may be performed without regard to a direction of the heat transfer fin 20.

As shown in FIG. 15A, a plurality of rectangular concave-convex shapes may be formed on the upper end portion and the lower end portion of the cut-and-erected portion 26.

Further, the number of the cut-and-erected portions 26 is not limited to the above embodiment, and the number of cut-and-erected portions 26 may be changed appropriately. For example, there may be four cut-and-erected portions 26 provided on the heat transfer fins 20 as shown in FIG. 15B.

In order to improve the leading edge effect, the cut-and-erected portion 26 may be folded multiple times from the proximal end toward the distal end of the cut-and-erected portion 26, as shown in FIG. 16A.

In addition, as shown in FIG. 16B, the cut-and-erected portions 26 may be installed by grooving the upper end portion (the leeward side end portion) or the lower end portion (the windward side end portion) of the heat transfer fin 20 and erecting the cut-and-erected portions 26.

Fourth Embodiment

Hereinafter, a heat exchanger (Hereinafter, referred to as an evaporator) for refrigerator according to a fourth embodiment of the present disclosure will be described.

The evaporator 100 according to the fourth embodiment is different from the first embodiment in a direction of offsetting the heat transfer fins 20. That is, in the first embodiment, the heat transfer fins 20 are offset in the column direction. However, in the fourth embodiment, as shown in FIG. 17, the heat transfer fins 20 are offset in a width direction from the plane's perspective.

The width direction is perpendicular to the column direction and the vertical direction (the air flow direction).

Hereinafter, a detailed configuration of the heat transfer fin 20 applied to the evaporator 100 according to the fourth embodiment of the present disclosure will be described.

The heat transfer fin 20 is for increasing a heat exchange area between the evaporator 100 and the air as described in the first embodiment. As shown in FIG. 17, the heat transfer fin 20 is a thin plate member having a thermal conductivity through which the pair of heat transfer pipes 10 are installed. In addition, the pair of heat transfer pipes 10 are spaced apart from each other in the width direction of the heat transfer fins 20 when the heat transfer fins 20 are viewed from the plane's perspective.

The heat transfer fins 20 are continuously arranged in substantially parallel along an axial direction of the heat transfer pipe 10, and the heat transfer fins 20 arranged in this manner are formed in multiple stages from the windward side to the leeward side. In addition, the heat transfer fins 20 are arranged such that the fin pitch of the leeward side is narrower than the windward side, that is, the heat transfer fins 20 positioned on the windward side are arranged at a predetermined first fin pitch, while the heat transfer fins 20 in a plurality of stages positioned on the leeward side are arranged at a predetermined fin pitch smaller than the first fin pitch.

As shown in FIG. 18, the evaporator 100 of the present embodiment has the plurality of the heat transfer fins 20 which are configured such that center lines L1 (hereinafter referred to as first center lines L1) of the width direction of the heat transfer fins 20 from the plane's perspective and center lines L2 (hereinafter referred to as second center lines L2) of the pair of heat transfer pipes 10 passing through the heat transfer fins 20 are spaced apart from each other by a predetermined distance ΔL.

More specifically, as shown in FIG. 18, the evaporator 100 is provided with the heat transfer fin 20 (Hereinafter, referred to as a first heat transfer fin 20A) having the first center line L1 positioned on one side (the right side) in the width direction of the second center line L2 and the heat transfer fin 20 (Hereinafter, referred to as a second heat transfer fin 20B) having the first center line L1 positioned on the other side (the left side) in the width direction of the second center line L2. In addition, the spaced distances ΔL between the first center line L1 and the second center line L2 are the same for each heat transfer fin 20, but are not limited thereto. It is also possible for the first heat transfer fin 20A and the second heat transfer fin 20B to be spaced apart from the center line L2 of the heat transfer pipes 10 by different spaced distances ΔL, or the spaced distances ΔL of each of the heat transfer fins 20 may be appropriately changed.

In addition, as shown in FIGS. 17 and 18, the heat transfer fins 20 disposed at the upper and lower stages adjacent to each other are offset by a predetermined distance Y in the width direction.

Here, of the heat transfer fins 20 disposed on the leeward side at the second fin pitch, the heat transfer fins 20 arranged at the upper and lower stages adjacent to each other are offset by a predetermined distance Y in the width direction.

More specifically, as shown in FIG. 17, for the heat transfer fins (20) on the leeward side, of the heat transfer fins 20 arranged at the upper and lower stages adjacent to each other, for example, the heat transfer fins 20 positioned in the upper stage are all formed as the first heat transfer fin 20A, and the heat transfer fins 20 positioned in the lower stage are all formed as the second heat transfer fin 20B.

Accordingly, the offset distance Y of the heat transfer fins 20 disposed at the upper and lower stages is twice the spaced distance ΔL between the first center line L1 and the second center line L2.

However, in the first heat transfer fin 20A, when the spaced distance ΔL becomes long, the distance from the heat transfer pipe 10 on the right side to the right side end of the first heat transfer fin 20A becomes long, so that heat exchange at the right side portion of the first heat transfer fin 20A becomes difficult and the heat exchange efficiency of the first heat transfer fin 20A is reduced. This is the same as in the second heat transfer fin 20B.

Therefore, the spaced distance ΔL is set to a predetermined value or less. For example, the spaced distance ΔL is set for the offset distance Y to be less than or equal to ½ of the height in the vertical direction of the heat transfer fin 20.

In the evaporator 100 as described above, since the heat transfer fins 20 disposed at the upper and lower stages adjacent to each other are offset by a predetermined distance Y along the width direction, air flow is disturbed when the air flows between the heat transfer fins 20 on the leeward side and the heat transfer fins 20 on the windward side. Therefore, thermal boundary layers developed when the air flows along the heat transfer fins 20 on the windward side may be broken before the air flows in the heat transfer fins 20 on the leeward side, so that the heat exchange efficiency may be improved.

In addition, since the offset distance Y is set to be less than ½ of the height of the heat transfer fin 20 in the vertical direction, the heat exchange efficiency of the heat transfer fin 20 may be ensured to be higher than a certain level while the heat transfer fins 20 may be offset in the width direction.

However, the present disclosure is not limited to the above embodiments.

For example, in the above embodiment, of the heat transfer fins 20 arranged in the upper and lower stages adjacent to each other, the heat transfer fins 20 positioned in the upper stage are all the first heat transfer fins 20A and the heat transfer fins 20 positioned in the lower stage are all the second heat transfer fins 20B, but not all the first heat transfer fins 20 need to be the first or second heat transfer fins 20A or 20B. For example, some of the heat transfer fins 20 positioned in the upper stage may be formed as the first heat transfer fin 20A and some of the heat transfer fin 20 positioned in the lower stage maybe formed as the second heat transfer fin 20B.

More specifically, as shown in FIG. 19, every other heat transfer fins 20 positioned in the upper stage are formed as the first heat transfer fin 20A in the column direction and every other heat transfer fins 20 positioned in the lower stage are formed as the second heat transfer fins 20B in the column direction.

In addition, in this embodiment, of the heat transfer fins 20 arranged in the upper and lower stages adjacent to each other, the heat transfer fins 20 positioned in the upper stage are formed as the first heat transfer fin 20A, and the heat transfer fins 20 positioned in the lower stage are formed as the second heat transfer fins 20B. However, as shown in FIGS. 20A and 20B, the heat transfer fins 20 positioned in the lower stage may have the first center line L1 and the second center line L2 correspond to each other. In this case, the heat transfer fins 20 positioned in the upper stage may be formed as the first heat transfer fin 20A or the second heat transfer fin 20B.

In addition, in the above embodiment, the heat transfer fins 20 disposed at the upper and lower stages adjacent to each other are offset only in the width direction. However, it is also possible for the heat transfer fins 20 to be offset in both the column direction and the width direction.

More specifically, as shown in FIG. 21, the heat transfer fins 20 disposed at the upper and lower stages adjacent to each other are offset by a predetermined first distance X in the column direction and a predetermined second distance Y in the width direction. In this case, the predetermined first distance X and the predetermined second distance Y may be equal to or different from each other.

In addition, the present disclosure is not limited to the first embodiment, the second embodiment, the third embodiment, and the fourth embodiment. Various modifications are possible without departing from a purpose of the present disclosure. 

1. A heat exchanger for refrigerator comprising: a plurality of heat transfer fins continuously arranged in multiple stages from a windward side to a leeward side, wherein the heat transfer fins disposed at upper and lower stages adjacent to each other are offset in one of a column direction and a width direction from the plane's perspective.
 2. The heat exchanger for refrigerator according to claim 1, wherein the heat transfer fins disposed at the upper and lower stages adjacent to each other are offset by a first distance in the column direction and offset by a second distance in the width direction.
 3. The heat exchanger for refrigerator according to claim 1, wherein the heat transfer fins positioned on the windward side are spaced apart from each other at a first fin pitch, and wherein the plurality of heat transfer fins positioned in multiple stages on the leeward side are spaced apart from each other at a second fin pitch smaller than the first fin pitch.
 4. The heat exchanger for refrigerator according to claim 3, wherein the heat transfer fins disposed at the upper and lower stages adjacent to each other among the heat transfer fins spaced apart from each other by the second fin pitch are offset by a predetermined distance in one of the column direction and the width direction.
 5. The heat exchanger for refrigerator according to claim 4, wherein an offset distance in the width direction is equal to or less than ½ of a height of the heat transfer fin.
 6. The heat exchanger for refrigerator according to claim 1, wherein leeward side end portions of the heat transfer fins are folded obliquely with respect to an air flow direction.
 7. The heat exchanger for refrigerator according to claim 6, wherein the heat transfer fins include body portions positioned on the windward side and folded portions formed by being folded from the leeward side end portions of the body portions, and wherein the folded portion is folded at an angle of no less than 5 degrees and no more than 20 degrees with respect to the body portion.
 8. The heat exchanger for refrigerator according to claim 3, wherein in the heat transfer fins disposed at the upper and lower stages adjacent to each other among the heat transfer fins disposed at the second fin pitch, windward side end portions of the heat transfer fins of the upper stage and leeward side end portions of the heat transfer fins of the lower stage are spaced apart from each other by less than 1 mm in a vertical direction.
 9. The heat exchanger for refrigerator according to claim 1, wherein the heat transfer fin includes a cut-and-erected portion that is cut and erected toward a heat transfer fin facing the heat transfer fin in the column direction.
 10. The heat exchanger for refrigerator according to claim 9, wherein height from a proximal end to a distal end of the cut-and-erected portion is smaller than the fin pitch between the heat transfer fins continuously disposed and facing each other.
 11. The heat exchanger for refrigerator according to claim 10, wherein at least one of an upper end portion and a lower end portion of the cut-and-erected portion forms a concave-convex shape.
 12. The heat exchanger for refrigerator according to claim 1, further comprising: a pair of heat transfer pipes passing through the heat transfer fins, wherein a first center line in the width direction of the heat transfer fins and a second center line between the pair of heat transfer pipes are spaced apart from each other by a predetermined distance.
 13. The heat exchanger for refrigerator according to claim 12, wherein the heat transfer fins form a first heat transfer fin in which the first center line is positioned on one side in the width direction of the second center line and a second heat transfer fin in which the first center line is positioned on the other side in the width direction of the second center line.
 14. The heat exchanger for refrigerator according to claim 13, wherein among the heat transfer fins disposed at upper and lower stages adjacent to each other, the heat transfer fin positioned at the upper stage is formed as one of the first heat transfer fin and the second heat transfer fin and the heat transfer fin positioned at the lower stage is formed as the other of the first heat transfer fin and the second heat transfer fin.
 15. The heat exchanger for refrigerator according to claim 13, wherein among the heat transfer fins disposed at the upper and lower stages adjacent to each other, the first centerline of the heat transfer fins positioned at one of the upper stage and the lower stage is aligned with the second centerline, and wherein the heat transfer fins positioned at the other one of the upper stage and the lower stage are formed as one of the first heat transfer fin and the second heat transfer fin.
 16. A refrigerator comprising the heat exchanger for refrigerator according to claim
 1. 